So, here is my list :
1) ETH / Modula Systems Lilith : functional until 3 years ago, need to get it running again.
Used as a basis to build my Lilith emulator "Emulith"
These have always been rare, only several hunderd produced.
Survivors : around 10 units I know about. Currently running : none that I know of.
( BTW Bear : in the meantime I obtained a diskimage that could help you getting yours running again. )
2) Pascal Microengine. Rare ? I truely don't know.
3) Datapoint 2200 with Floppy & Cartridge disk drive. Why are these rare ? They once were everywhere...
4) Cogar / Singer / ICL 1501. A 1973 personal computer. Looking for a cartridge disk controller for these. Used to be quite common.
5) Philips P856 : 70's 16 bit TTL computer on 74181 basis. Sort of PDP11 class machine, more powerfull, more complex, very much less software.
6) Philips P854 : As above, reimplemented on AMD2901 basis.
7) Data General MP/200 : AMD2901 based Nova
8 ) PDC Clipper : C64 laptop. Hope to document this in a few weeks time.
9) SWTPC CT64
10) And a Lisa XL that boots 7 different operating systems from it 260 MB internal IDE harddisk. That last bit is of course a later addon, P. Schaefers IDEfile unit.
( Lisa OS3.1, OS2.0, Workshop, Macworks XL, Macworks+. Xenix 3.0, Uniplus )
AMD2901 seems to be the dominant CPU in this household !
Jos